Tool holder



May 26, 1925.

A. R. RIDDERSTROM TOOL HOLDER FiledA M a Vy 6, 1920 2 Sheets-Sheet 1 f 7?/1/6 @7207719111 J?, Jden'srom May 26, 1925. 1,539,057

A. R. RIDDERSTROM TOOL HOLDER Filed May 6, 1920 2 Sheets-Sheet 2 Patented May 26, 1925.

UNITED STATES PATENT OFFICE...A

ANDREW E'. RIDDERSTROM, OF' NAHANT, MASSACHUSETTS, ASSIGNOR, BY MESNE ASSIGNMENTS, '10 THOMAS C. BOWEN, OF SWAMPSCOTT, tIASSACHU'SETTS.

TOOL HOLDER.

Application filed May 6, 1920. Serial N'o.' S79 50.

To ZZ whom it 97mg/ concern.'

` Be it` known that I, ANnnnw Rosnn'r RIDDnns'rnoM, a citizen of the United States, and resident of Nahant, in the county oit Essex and Conmionwealth oli Massachusetts, have invented a new and uset'ul Improvement in Tool Holders, ot which the itollowing is a specilication.

The present invention relates to tool holders, and more particularly to rotatable holders for the butling heads of builing or polishing machines, such as are used to bull or polish the Shanks ot shoe soles during` the manufacture ol shoes.

llhcn the sand paper or other abrasive that is mounted upon the bulrlng headv becomes worn through use, the bulling head is removed, Vthe worn sand paper is replaced by a 'fresh sheet, and the head is then returned to its holder. During` the removal olf the butiing head trom, and its return to, the holder, .it has been customary hitherto either to stop the machine altogether by disconnecting it from its source oi power, or `to hold the tool holder and its driving shaft stationary while the driving belt was permitted to slip over the driving pulley keyed to the driving shaft. As it is necessary to replace the worn sand paper at lirequent intervals, both of these methods involve the loss ot considerable valuable time and the latter method is further objectionable because subjecting the machinery to unnecessary andnndesirable wear and tear.

An object ot the present invention, ac- (ixordingly, is to provide a tool holder ot the above-designated character that shall be adapted to permitthe removal oi' the tool, and its replacement, during the rotation of the tool holder and .without necessitating stopping the machine or subjecting it to unnecessary wear.

lilith this object in view, a feature of the invention resides in an improved tool holder that is provided with separable jaws that may be readily separated duringthe operation of the machine to permit the removal of the tool. rlhe jaws are normally maintained in eilective position, and are preterably screw threaded, .so that the correspondingly screw-threaded stem ot' a tool may be readily inserted between, and automatically clutched by the jaws. Owing to the action of the screw threads, furthermore, the parts ot the tool are tightened together when clutched, causing the sand paper or other abrasive to be tirmly clamped in position.

A Ylurther object of Vthe .invention is to sin'ipl'ity and improve upon tool holders of the class herein considered, rendering them simpler and more rugged in coiistruction, cheaper to nnnn'itacture and more etl'ective and reliable in operation.

lilith these ends in view, the invention consists of the improved tool holder hereina'lter described, illustrati-al in the accompanying drawings, and defined in the appended claims.

ln the drawings, illustrating a preferred en'ibodiment of the present invention, Fig. l is a side elevation, showing the operative portion ot a builing machine having` the present invention embodied therein; Fig. 2 is a central vertical sectional view; and Figs. 3, l and 5 are sectional views, taken upon the lines 3--; lf-t and 5-5 respectively, o'l Fig. 2.

'lhe rotatable tool holder olf the present invention comprises two vertically disposed, relatively i'novable jaws 2 that are normally maintained `in their eli'ective positions, as indicated in the drawings, to clutch the stem /l of a tool. Upon the jaws being momentarily separated, the tool will drop outl from between them. The removal of the tool may thus be easily and readily effected during the rotation of the tool holder. The tool may be as easily and readily reclutched while the tool holder rotating, To this end, the jaws are adapted to be returned to eli'ective positions immediately upon the release ot the momentary jaw-separating means, and, in the specific embodiment oit the invention that is herein illustrated and described, they are provided with screw threads 5 and the tool stem 4 is similarly threaded at G. Upon the threaded end ot the stem being positioned at the lower ends ot the jaws, therefore, the rotation ot the tool holder will automatically cause the tool stem to be drawn gradually into position between the jaws,

which will then clutch the tool as firmly as before.

The mechanism whereby the jaws are normally maintained in eilective position, and whereby they niay be momentarily separated, will now be described. The jaws are mounted within an intermediate, longitudinal., diametrical slot 8 in the lower enlarged head l0 of a vertically disposed driving shaft l2 that is mounted to rotate in bearings let and 16 of a. frame or support 18. rlhe slot 8 extends nearly throughout the length of the enlarged head l0, but not through the lower end thereof. The jaws are intermediately pivoted upon a pinL 2O that" is diametrically screwed into, or otherwise secured to, the shaft, at right angles to the plane of the slot 8. rllhe tail ends 22 of the jaws are respectively adapted to he engaged by oppositely disposed cams 2a'- provided upon the upper interiorwall of a vertically disposed, cylindrical sleeve 26 that encloses the greater` part of the enlarged head l() and the jaws mounted thereon. The head of the pin 2O is positioned within a. slot 2S that extends transversely across the sleeve through a quarter circumference of the cylinder, rlhe rotative movement of the sleeve relatively to the shaft is thus limited to ninety degrees. The head of the pin serves also'partly to support the sleeve upon the shaft head. Y

lVhen one end wall SO of the slot engages the head of the pin, at one off the limits of rotative moven'ientof the sleeve, the cams 2li are positioned ninety vdegrees awa-y 'from the tail ends 22 of -the jaws, so that the tail ends are permitted to separate and the jaws to close in to 'ai-ds each other into elfective position, as illustrated. 'lhe agency 'for thus closing,` the jaws in towards each other comprises oppositely disposed cams 32 interiorly vprovided upon the lower wall of the sleeve and acting' directly, one upon each jaw end of the jaws. rThe cams 32 are angularly ninety degrees removed from the cams 2st, so as to permit their acting' upon the j aw ends of the jaws at a` time when the tail ends are free from the restraining influence of the cams 24. Conversely, by this construction, the cams 2li will be adapted to act upon the tail ends of the jaws when the jaw ends are out of contact with the cams rlhe slot 2S is positioned angularly midway between adj acentcams of the pairs of cams 2-t and 32. lVhen the other' wall 34tof the` slot 28 engages the head of the pin 20, at the other limit of rotative movement of the sleeve, therefore, the cams will act upon the tail ends 22 to effeet the opening' of the jaws. By a simple, ninety-degree rotation of the sleeve 2G relatively to the shaft, therefore, the jaws may be readily separated and, by a reverse rotation, as readily returned to effective clutching; position. rllhe specific actuating meehanism for the jaws that has been hereinbefore described is not claimed herein, the invention residing not in structural details and mechanical movements, but in the combination of elements whereby t-he purpose of the invention is attained.

The driving shaft l2, with the tool holder mounted thereon, is adapted to be rotated in its bearings by a belt passing over a driving' pulley 3G that isiixed to the drivingshaft in any desired manner. To remove the. tool from the tool holder, it is not necessary either to stop the machine or to hold the drivingv shaft stationary while the belt is 'permitted to slip over the pulley, as has been the custom, heretofore. All that is necessary is to touch the sleeve 2G lightly for a moment with the hand to retard its rotation relative-ly rto that of the driving;` shaft. During' themoment that the sleeve is thus held against full rotation with the shaft, the shaft, continuing to rotate, and the jaws that are pivoted thereon rotating therewith, the cams 24.1: of the relatively stationary'sleeveavill engage the tail ends of the aws, causing the jaw ends to separate, 'and permitting the tool to drop out from between them by gravity.

rllhe jaws should be in'nnediately returned to their effective positions so as to be in readiness to reclutch the tool. To bring,- this about, the sleeve, according` to the present embodiment of the invention, is yield- .ingly maintained in the illustrated, jawclosing` position, so as to be immediately returned thereto when the operator, a'ftei* touching it lightly to effect a separation of the jaws, as above described, removes his hand. Oneend 38 of a spring et() that is coiled about the shaft is secured thereto and the other end'42 is mounted within any one e'f a plurality of slots lll provided upon the upper end of the sleeve. rl`he spring; acts to maintain the tool holder yielding-ly in the normal, illustrated position. The tension of the spring, acting yieldingly to return the tool holder to its normal, effective position may be adjusted by mounting the end l2 of the 'spring' in oneor another of the slots 44.

The tool holder of the present invention is thus adaptedto occupy two positions in one of which, its normal position, it is effective. to clutch 'a tool and in the other of which it is ineffective. The tool holder is yieldingly maintained in its normal position so as to be in readiness to reclutch the tool.

The tool illustrated in the drawings is a buliing head of separable parts comprising, in addition to the threaded stem t, a coni- Cally recesseth flanged' hub 4G freely centrally mounted thereon, a felt'disk 48 glued or otherwise secured to the hub, and a sheet 50 of sandpaper or othervabrasive loosely interposed between the disk and the head of the stem Il. The lower end 51 of the shaft head 10 is conically tapered so as to fit snugly within the conical recess of the hubtG and isaxially bored at 53 to receive the stem -Lt and guide it to thejaws 2. The same act lwhich automatically draws the tool inwardly into position upon the tool holder, therefore, during the rotation of the sha'ft,canses the hnb to become securely positioned upon the end of the shaft and serves to clamp the sand-paper sheet tightly in place between the head ot the stem and the felt pad. To further the clamping action, the head of the stem is enlarged, as shown at 52.

lhe invention is not limited to the specilic enlliodiment thereof that is herein illustrated and described, but may be modified within the skill et the artisan without departing 'from its spirit and scope as defined in the appended claims.

Vilhat is claimed is:

l. ln combination, a rotatable tool holder having relatively movable, screw-threaded jaws adapted to occupy a normal position when not clutching a tool and a stop separated from the jaws, a tool comprising a screw-threaded stem provided with a terminal head, a hub and a disk loosely and slidably monnted on the stem, and a sandpaper sheet interposed between the disk and the head, and means 'lor rotating the tool holder to canse the stem to be threaded'into position between the jaws when the aws occupy the normal position during the rotation of the tool holder to cause the stop to engage the hub tightly and to canse the sandpapersheet to become tightly clamped between the disk and the head, and means for separating the jaws to release the tool during the rotation ot the tool holder, whereby disassociation ot the tool parts is expedited by tacilitating detachability from the tool holder.

Q. In combination', a rotatable tool holder havingrelatively movable, screw-threaded jaws adapted to occupy a normal position when not clutching' a tool and a stop separated trom the jaws, a tool comprising a screw-threaded stem provided with a terminal head, a hub and a disk loosely and slidably mounted on the stem, and a sandpaper sheet interposed between the disk and the head, means -tor rotating the tool holder to cause the stem to be threaded into position between the jaws when the jaws occupy the normal position during the rotation of the tool holder to cause the stop to engage the hub tightly and to canse the sandpaper sheet to become tightly clamped between the disk and the head, the tool holder having a cylindrical sleeve adapted to be rotated with respect to the tool holder and having two pairs ot interior, oppositely disposed cams, the cams ot one pair being adapted to engage the jaws to etllect a relative movement of the jaws into the normal position, and means for normally maintaining the sleeve in a position relatively to the tool holder such that the jaws are maintained by the cams ot the said one pair in the normal positions, the cams ot the other pair being adapted to engage the jaws to separate them, and the sleeve being adapted to be actuated during the rotation of the tool holder to cause the cams of the second-named pair to separate the jaws to release the tool, whereby disassoeiation of the tool parts is eX- pedited by facilitating detachability trom the tool holder.

3. A tool holder having a cylindrical sleeve provided with a transverse slot ex-V tending over a quarter circim'iference of the cylinder' and with two pairs ot interior, oppositely disposed cams, the cams of each pair being removed .ninety degrees from the cams of the other pair and the slot being positioned angnlarly midway between adjacent cams ot the different pairs, a pin mounted in the holder having a head extending into the slot ot the sleeve, two jaws intermediately pivoted within the sleeve about the pin, and means :tor maintaining' an end wall of the slot in engagement with the head ot the pin, one pair oit the cams then engaging the jaw ends of the jaws to maintain the jaws in effective position', the sleeve being adapted to be rotated so as to cause the other end wall of the slot to engage the head of the pin, the other pair of cams then engaging the tail ends of the jaws to etect the opening ot the jaws and to permit the ready removal of the tool.

In testimony whereof, I have hereunto subscribed my name this 30th day of April, 1920.

ANDREl/V R. RIDDERSTROM. 

